EP0597335B1 - Process and apparatus for renerating used foundry sand - Google Patents
Process and apparatus for renerating used foundry sand Download PDFInfo
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- EP0597335B1 EP0597335B1 EP93117552A EP93117552A EP0597335B1 EP 0597335 B1 EP0597335 B1 EP 0597335B1 EP 93117552 A EP93117552 A EP 93117552A EP 93117552 A EP93117552 A EP 93117552A EP 0597335 B1 EP0597335 B1 EP 0597335B1
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- sand
- container
- treatment container
- friction
- cleaning
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C5/00—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose
- B22C5/04—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose by grinding, blending, mixing, kneading, or stirring
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C5/00—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose
- B22C5/18—Plants for preparing mould materials
Definitions
- the invention relates to a method for the regeneration of foundry sand by circulating the old sand in a processing room and thereby bringing about the friction forces breaking up the binder shell and releasing the grain of sand from the old sand particles, and the resulting mixture of sand and binder particles being physically cleaned while enriching the sand content. Furthermore, the invention relates to a device for the regeneration of foundry sand with a processing container, which has a controllable inlet, an outlet on its circumference close to the floor and at least one rotating tool rotating above the floor.
- thermal-mechanical methods are also known, in which, for example, the old sand is circulated in a single processing container and simultaneously or batchwise exposed to a burner flame and is further mechanically loaded by means of mechanical friction and scouring tools in order to break the binder casing (EP 0 125 384 A1) .
- the thermal pretreatment and the mechanical aftertreatment take place in separate rooms.
- the mechanical processing room the thermally pretreated old sand is circulated using rotating tools and at the same time fluidized using compressed air coming in from below and this fluidizing air is drawn off above the sand surface.
- the binder casing is to be separated from the sand particles by the rotating tools, unless already done in the thermal pretreatment.
- the detached binder particles are to be constantly removed with the fluidizing air will. Apart from the problematic thermal pretreatment, the efficiency in the mechanical stage is poor.
- the invention has for its object to effectively regenerate old sands with mixtures of different binders, especially problematic binders such as bentonite and / or water glass, in a purely mechanical way.
- this object is achieved in that a part of the mixture of substances is drawn off from the processing space into a separate cleaning space and cleaned after passing through the friction zone, and the pre-cleaned old sand is returned to the processing space.
- the old sand in the processing room is only subjected to friction and pressure forces, the sand batch contained in the processing room bearing its own weight on the friction zone, so that intensive mechanical pressure is exerted by the processing tools on the particles, but also intense friction and abrasion forces between the particles, which on the one hand to rub off the binder shell, and on the other hand to shred of the particles of the binder casing so that two relatively sharply separated grain spectra, sand particles on the one hand and binder particles on the other hand, are present in the mixture of substances leaving the friction zone.
- This mixture of substances is drawn off from the friction zone of the processing area and transferred to a separate cleaning area, in which the binder particles are largely separated.
- the used sand pre-cleaned in this way is transferred again from the cleaning chamber into the processing room in order to rub off any adhering binder in a further treatment.
- These circulation cycles are carried out several times if necessary and the finally sufficiently binder-free regenerated sand is returned to the production process. It is essential for the method according to the invention to separate the processing and cleaning stages, so that each can be carried out under optimal conditions. It is particularly important to note that there is no fluidization in the processing area and that the batch contained in the processing area has the lowest possible pore volume in order to allow the friction and abrasive forces to act on the largest possible surface of the sand particles.
- the old batch of sand moves under gravity from top to bottom into the friction zone in the processing space and the material mixture is drawn off essentially horizontally in the area.
- the entire sand batch of the processing space is loaded on the friction zone with the previously described advantage of high particle density and low pore volume in the friction zone.
- the mixture of substances is drawn off directly from the area of the friction zone in order to feed it for pre-cleaning (separation of the binder particles).
- the mixture of substances is mechanically displaced outward in the region of the friction zone and pneumatically conveyed away at the periphery of the processing space.
- the mixture of substances is displaced in the area of the friction zone by the pressure and circulation forces.
- the pneumatic conveying away of the mixture of substances at the periphery of the processing space creates a negative pressure near the friction zone, which contributes to reducing the pore volume of the bed in the friction zone.
- the invention is based on the device mentioned at the beginning (EP 0 343 272), which according to the invention is characterized in that outside the processing container a cleaning chamber for separating sand and binder particles is provided, which is arranged in a conveyor circuit connecting the outlet of the processing container with its inlet.
- the processing container and the cleaning chamber are in a closed conveyor circuit. After the untreated old sand has been placed on the processing container, it may pass through the cleaning chamber and the processing container several times and is continuously cleaned of the binder particles accumulating in the friction zone.
- a buffer container can be arranged between the cleaning chamber and the processing container in order to obtain a homogenization of the mixture of substances in front of the processing zone and to ensure that the bulk material column in the processing container is always the same.
- the reaming tool rotates directly above the bottom of the processing container and the drain is arranged in the rotating plane of the reaming tool. The mixture of substances is therefore removed directly from the friction zone.
- the reaming tool can have two or more rice arms which extend into the region of the circumference of the processing container.
- the pressure on the friction zone can be increased in that a pressure generating element acting on the sand filling, for example a worm, acts above the grinding tool. is arranged.
- the conveyor circuit is formed by a pneumatic conveyor device which has an injector at the outlet of the processing container and a conveyor line leading from there into the cleaning chamber.
- the cleaning chamber can basically have any structure. In connection with a pneumatic conveying device, a design is recommended in which the cleaning chamber is designed as a centrifugal separator and has a dust extraction.
- the processing container can have a plurality of processes distributed around the circumference in order to increase the circulation quantity, and possibly also to be able to control it.
- a pneumatic delivery line is connected to each outlet.
- a processing container 1 can be seen, which has an inlet 2 on its top, the is controllable by means of a flap 3.
- the processing container 1 has an outlet 5.
- the outlet 5 opens into a pneumatic conveyor line 6 with a rising conveyor.
- the pneumatic delivery line 6 connects the outlet 5 to a cleaning chamber 7 (see FIG. 2), which in the exemplary embodiment shown is designed as a centrifugal separator and is placed on a buffer silo 8.
- the buffer silo 8 in turn is connected to the processing container 1 via the inlet 2, so that a closed conveyor circuit is produced from the outlet 5 of the processing container 1 via the riser 6, the cleaning chamber 7, the buffer container 8 and the inlet 2 of the processing container.
- the used sand accumulating in the foundry is collected in a silo 9 and, from there, pneumatically or mechanically, as indicated by the conveying line 10, it is fed to the cleaning chamber 7 and from there via the buffer silo into the processing container 1, to be recirculated into the cleaning chamber 7 after it has passed through the outlet 5 and the riser 6.
- a branch line 11 is connected to the riser 6, which leads into a silo 12, in which the regenerated sand is conveyed after a certain number of working cycles in the processing container 1.
- the sand is drawn off from the regenerated silo 12 into the sand preparation and / or into the core production of the foundry.
- the cleaning chamber 7 and the silos 9, 10 are in turn connected to the suction line 13 of a dedusting system 14.
- a revolving reaming tool 15 is arranged within the processing container 1 directly above its bottom 4, which several to Rough arms 16 reaching approximately to the circumference of the processing container 1.
- the reaming tool 15 is rotated by a drive shaft 17 mounted beneath the floor and penetrating it.
- the processing container 1 is equipped on the inside with a wear layer 18.
- the sand column located within the processing container 1 bears on the friction zone 19 swept by the reaming tools 15.
- the used sand mainly runs into the friction zone 19 in the central region.
- the sand particles in the friction zone are exposed to intense frictional forces, which rub off the binder shell adhering to them.
- the sand particles and the particles of the binder casing migrate outward from the friction zone 19 into the outlet 5 and are transported there by the conveying air blown in at 20 via the riser 6 into the cleaning chamber 7.
- the pneumatic conveying creates a negative pressure at outlet 5, which leads to a reduction in the pore volume in the friction zone 19.
- the sand particles are separated by centrifugal and gravitational forces, while the binder particles reach the dedusting system 14 via the suction line 13.
- the pre-cleaned used sand arrives from the cleaning zone 7 into the buffer tank 8 and after a corresponding dwell time back into the processing tank 1. After several passes, binder-free regenerated sand is finally obtained, which is drawn off into the silo 12 via the conveying line 11.
Description
Die Erfindung betrifft ein Verfahren zum Regenerieren von Gießereialtsand, indem der Altsand in einem Bearbeitungsraum umgewälzt und dabei auf die Altsandpartikel die Binderhülle aufbrechende und vom Sandkorn lösende Reibungskräfte zur Wirkung gebracht werden und das entstehende Stoffgemisch aus Sand und Binderpartikel unter Anreicherung des Sandanteils physikalisch gereinigt wird. Ferner bezieht sich die Erfindung auf eine Vorrichtung zum Regenerieren von Gießereialtsand mit einem Bearbeitungsbehälter, der einen steuerbaren Zulauf, an seinem Umfang nahe über dem Boden einen Ablauf und wenigstens ein oberhalb des Bodens umlaufendes Reibwerkzeug aufweist.The invention relates to a method for the regeneration of foundry sand by circulating the old sand in a processing room and thereby bringing about the friction forces breaking up the binder shell and releasing the grain of sand from the old sand particles, and the resulting mixture of sand and binder particles being physically cleaned while enriching the sand content. Furthermore, the invention relates to a device for the regeneration of foundry sand with a processing container, which has a controllable inlet, an outlet on its circumference close to the floor and at least one rotating tool rotating above the floor.
Die Aufbereitung von Gießereialtsand ist aufgrund von Umweltschutz-Bestimmungen zur zwingenden Notwendigkeit geworden, um das Deponievolumen von Gießereialtsanden zu verringern. Alle bekannten Verfahren zielen darauf ab, den Formsand zurückzugewinnen und die Binder entweder ohne Umweltbelastung zu zerstören oder aber mit kleinem Volumen deponiefähig zu machen. Das Hauptproblem bei der Aufbereitung von Altsanden liegt in der Vielzahl verschiedener Binder organischer und anorganischer Art, die zur Entwicklung unterschiedlicher Aufbereitungsmethoden geführt haben. Bei organischen Bindern bieten sich vor allem thermische Verfahren an, da diese Binder thermisch nicht stabil sind. Diese thermischen Verfahren erfordern einerseits einen hohen Energieeinsatz, andererseits führen sie zur Gasemission, was einen zusätzlichen Aufwand in der Beseitigung umweltschädlicher Gase erfordert. Es sind deshalb in der Vergangenheit zunehmend mechanische Reib- und Scheuerverfahren untersucht worden, die bei anorganischen Bindern ohnehin die einzig wirksame Möglichkeit der Beseitigung der Binderschale auf dem Sandkorn sind.The processing of foundry sand has become an imperative due to environmental protection regulations in order to reduce the volume of landfills of foundry sand. All known processes aim to recover the molding sand and either destroy the binders without polluting the environment or with small volume to make landfill capable. The main problem with the processing of used sands is the large number of different binders, organic and inorganic, which have led to the development of different processing methods. In the case of organic binders, thermal processes are particularly suitable, since these binders are not thermally stable. On the one hand, these thermal processes require a large amount of energy, on the other hand, they lead to gas emissions, which requires additional effort in the removal of environmentally harmful gases. For this reason, mechanical friction and abrasion processes have been increasingly investigated in the past, which are anyway the only effective way of removing the binder shell on the grain of sand with inorganic binders.
Ferner sind kombinierte thermisch-mechanische Verfahren bekannt, bei denen beispielsweise in einem einzigen Bearbeitungsbehälter der Altsand umgewälzt und gleichzeitig oder absatzweise einer Brennerflamme ausgesetzt und ferner mittels mechanischer Reib- und Scheuerwerkzeuge mechanisch belastet wird, um die Binderhülle zu sprengen (EP 0 125 384 A1). Bei einem anderen bekannten Verfahren (EP 0 343 272 A1) findet die thermische Vorbehandlung und die mechanische Nachbehandlung in getrennten Räumen statt. In dem mechanischen Bearbeitungsraum wird der thermisch vorbehandelte Altsand mittels umlaufender Werkzeuge umgewälzt und gleichzeitig mittels von unten zutretender Druckluft fluidisiert und diese Fluidisierungsluft oberhalb der Sandoberfläche abgezogen. Durch die umlaufenden Werkzeuge soll die Binderhülle, soweit nicht schon in der thermischen Vorbehandlung geschehen, von den Sandpartikeln getrennt werden. Die abgelösten Binderpartikel sollen mit der Fluidisierungsluft ständig weggefördert werden. Abgesehen von der problematischen thermischen Vorbehandlung ist der Wirkungsgrad in der mechanischen Stufe mangelhaft.Combined thermal-mechanical methods are also known, in which, for example, the old sand is circulated in a single processing container and simultaneously or batchwise exposed to a burner flame and is further mechanically loaded by means of mechanical friction and scouring tools in order to break the binder casing (EP 0 125 384 A1) . In another known method (EP 0 343 272 A1), the thermal pretreatment and the mechanical aftertreatment take place in separate rooms. In the mechanical processing room, the thermally pretreated old sand is circulated using rotating tools and at the same time fluidized using compressed air coming in from below and this fluidizing air is drawn off above the sand surface. The binder casing is to be separated from the sand particles by the rotating tools, unless already done in the thermal pretreatment. The detached binder particles are to be constantly removed with the fluidizing air will. Apart from the problematic thermal pretreatment, the efficiency in the mechanical stage is poor.
Bei einem anderen, rein mechanischen Verfahren (DE 41 06 737 A1) wird der Altsand ausschließlich einer mechanischen Behandlung unterzogen, indem er in einer Scheuertrommel umgewälzt wird. Auch hierbei wird der entstehende Binderstaub pneumatisch weggefördert, was wiederum eine Fluidisierung, zumindest aber starke Durchlüftung der Behältercharge erforderlich macht. Auch ist dieses Verfahren vorwiegend nur für tongebundene Altsande geeignet.In another, purely mechanical process (DE 41 06 737 A1), the used sand is only subjected to a mechanical treatment by being circulated in a scrubbing drum. Here, too, the binder dust that is produced is pneumatically conveyed away, which in turn requires fluidization, or at least strong aeration, of the batch of containers. This method is mainly only suitable for old clay-bound sands.
Der Erfindung liegt die Aufgabe zugrunde, Altsande mit Gemischen verschiedener Binder, insbesondere auch problematischen Bindern, wie Bentonit und/oder Wasserglas, auf rein mechanischem Weg wirksam zu regenerieren.The invention has for its object to effectively regenerate old sands with mixtures of different binders, especially problematic binders such as bentonite and / or water glass, in a purely mechanical way.
Ausgehend von dem eingangs genannten Verfahren (EP 0 343 272) wird diese Aufgabe dadurch gelöst, daß ein Teil des Stoffgemischs nach Durchlaufen der Reibungszone aus dem Bearbeitungsraum in einen getrennten Reinigungsraum abgezogen und gereinigt und der vorgereinigte Altsand in den Bearbeitungsraum zurückgeführt wird.On the basis of the method mentioned at the beginning (EP 0 343 272), this object is achieved in that a part of the mixture of substances is drawn off from the processing space into a separate cleaning space and cleaned after passing through the friction zone, and the pre-cleaned old sand is returned to the processing space.
Bei dem erfindungsgemäßen Verfahren, das ohne eine thermische Vorbehandlung des Altsandes auskommt, wird der Altsand in dem Bearbeitungsraum ausschließlich Reibungs- und Druckkräften ausgesetzt, wobei die im Bearbeitungsraum enthaltene Sandcharge mit ihrem Eigengewicht auf der Reibungszone lastet, so daß ein intensiver mechanischer Druck von den Bearbeitungswerkzeugen auf die Partikel, aber auch intensive Reibungs- und Scheuerkräfte zwischen den Partikeln stattfinden, die einerseits zum Abreiben der Binderhülle, andererseits auch gleichzeitig zum Zerkleinern der Partikel der Binderhülle führen, so daß in dem die Reibungszone verlassenden Stoffgemisch zwei relativ scharf getrennte Kornsprektren, Sandpartikel einerseits und Binderpartikel andererseits, vorliegen. Dieses Stoffgemisch wird aus der Reibungszone des Bearbeitungsraums abgezogen und in einen getrennten Reinigungsraum übergeführt, in welchem die Binderpartikel weitestgehend abgetrennt werden. Der auf diese Weise vorgereinigte Altsand wird aus der Reinigungskammer erneut in den Bearbeitungsraum übergeben, um noch anhaftende Binderanteile in einer weiteren Behandlung abzureiben. Diese Umlaufzyklen werden ggf. mehrfach durchgeführt und der schließlich ausreichend binderfreie Regeneratsand wieder in den Produktionsprozeß gegeben. Wesentlich für das erfindungsgemäße Verfahren ist die Trennung der Bearbeitungs- und Reinigungsstufe, so daß jede bei für sie optimalen Bedingungen durchgeführt werden kann. Dabei ist insbesondere die Tatsache wichtig, daß im Bearbeitungsraum keine Fluidisierung stattfindet und somit die im Bearbeitungsraum enthaltene Charge ein geringst mögliches Porenvolumen aufweist, um die Reibungs- und Scheuerkräfte auf einer größtmöglichen Oberfläche der Sandpartikel wirksam werden zu lassen.In the method according to the invention, which does not require thermal pretreatment of the old sand, the old sand in the processing room is only subjected to friction and pressure forces, the sand batch contained in the processing room bearing its own weight on the friction zone, so that intensive mechanical pressure is exerted by the processing tools on the particles, but also intense friction and abrasion forces between the particles, which on the one hand to rub off the binder shell, and on the other hand to shred of the particles of the binder casing so that two relatively sharply separated grain spectra, sand particles on the one hand and binder particles on the other hand, are present in the mixture of substances leaving the friction zone. This mixture of substances is drawn off from the friction zone of the processing area and transferred to a separate cleaning area, in which the binder particles are largely separated. The used sand pre-cleaned in this way is transferred again from the cleaning chamber into the processing room in order to rub off any adhering binder in a further treatment. These circulation cycles are carried out several times if necessary and the finally sufficiently binder-free regenerated sand is returned to the production process. It is essential for the method according to the invention to separate the processing and cleaning stages, so that each can be carried out under optimal conditions. It is particularly important to note that there is no fluidization in the processing area and that the batch contained in the processing area has the lowest possible pore volume in order to allow the friction and abrasive forces to act on the largest possible surface of the sand particles.
Dies kann noch dadurch unterstützt werden, daß im Bereich der Reibungszone das Porenvolumen im Stoffgemisch reduziert wird. Dies wiederum kann auf verschiedene Art und Weise geschehen, beispielsweise durch zusätzlichen mechanischen Druck auf die Sandcharge, insbesondere im Bereich der Reibungszone, um eine Verdichtung der Schüttung zu erhalten. Als sehr wirksam hat sich auch erwiesen, wenn anläßlich des Abziehens des Stoffgemischs aus dem Bearbeitungsraum Luft aus der Reibungszone abgesaugt wird. Das erfindungsgemäße Verfahren geht gegenüber dem Stand der Technik einen geradezu konträren Weg, indem nicht Luft in den Bearbeitungsraum zugegeben, sondern der Bearbeitungsraum, insbesondere die Reibungszone möglichst luftfrei wird.This can be supported by reducing the pore volume in the material mixture in the area of the friction zone. This in turn can be done in various ways, for example by additional mechanical pressure on the sand batch, in particular in the area of the friction zone, in order to obtain a compaction of the bed. It has also proven to be very effective if air is sucked out of the friction zone when the substance mixture is removed from the processing space. The method according to the invention is almost a step ahead of the prior art contrary way, in that not air is added to the processing space, but the processing space, in particular the friction zone, is as free of air as possible.
In bevorzugter Ausführung ist vorgesehen, daß die Altsandcharge im Bearbeitungsraum unter Schwerkraft von oben nach unten in die Reibungszone bewegt und in dem Bereich das Stoffgemisch im wesentlichen horizontal nach außen abgezogen wird.In a preferred embodiment, it is provided that the old batch of sand moves under gravity from top to bottom into the friction zone in the processing space and the material mixture is drawn off essentially horizontally in the area.
Beim erfindungsgemäßen Verfahren lastet also die gesamte Sandcharge des Bearbeitungsraumes auf der Reibungszone mit dem zuvor beschriebenen Vorteil großer Partikeldichte und geringen Porenvolunens in der Reibungszone. Ferner wird das Stoffgemisch aus dem Bereich der Reibungszone unmittelbar nach außen abgezogen, um es der Vorreinigung (Abtrennung der Binderpartikel) zuzuführen.In the method according to the invention, therefore, the entire sand batch of the processing space is loaded on the friction zone with the previously described advantage of high particle density and low pore volume in the friction zone. In addition, the mixture of substances is drawn off directly from the area of the friction zone in order to feed it for pre-cleaning (separation of the binder particles).
In weiterhin vorteilhafter Ausführung ist vorgesehen, daß das Stoffgemisch im Bereich der Reibungszone mechanisch nach außen verdrängt und an der Peripherie des Bearbeitungsraums pneumatisch weggefördert wird.In a further advantageous embodiment it is provided that the mixture of substances is mechanically displaced outward in the region of the friction zone and pneumatically conveyed away at the periphery of the processing space.
Das Stoffgemisch wird im Bereich der Reibungszone durch die Druck- und Umwälzkräfte nach außen verdrängt. Durch die pneumatische Wegförderung des Stoffgemischs an der Peripherie des Bearbeitungsraums wird nahe der Reibungszone ein Unterdruck erzeugt, der zur Reduzierung des Porenvolumens der Schüttung in der Reibungszone beiträgt.The mixture of substances is displaced in the area of the friction zone by the pressure and circulation forces. The pneumatic conveying away of the mixture of substances at the periphery of the processing space creates a negative pressure near the friction zone, which contributes to reducing the pore volume of the bed in the friction zone.
Zur Lösung der Aufgabe in vorrichtungstechnischer Hinsicht geht die Erfindung aus von der eingangs genannten Vorrichtung (EP 0 343 272), die sich erfindungsgemäß dadurch auszeichnet, daß außerhalb des Bearbeitungsbehälters eine Reinigungskammer zum Trennen von Sand- und Binderpartikel vorgesehen ist, die in einem den Ablauf des Bearbeitungsbehälters mit dessen Zulauf verbindenden Förderkreis angeordnet ist.To achieve the object in terms of device technology, the invention is based on the device mentioned at the beginning (EP 0 343 272), which according to the invention is characterized in that outside the processing container a cleaning chamber for separating sand and binder particles is provided, which is arranged in a conveyor circuit connecting the outlet of the processing container with its inlet.
In vorrichtungstechnischer Hinsicht liegen also der Bearbeitungsbehälter und die Reinigungskammer in einem geschlossenen Förderkreis. Nach Aufgabe des unbehandelten Altsandes auf den Bearbeitungsbehälter durchläuft dieser ggf. mehrfach die Reinigungskammer und den Bearbeitungsbehälter und wird dabei laufend von den in der Reibungszone anfallenden Binderpartikeln gereinigt.In terms of device technology, the processing container and the cleaning chamber are in a closed conveyor circuit. After the untreated old sand has been placed on the processing container, it may pass through the cleaning chamber and the processing container several times and is continuously cleaned of the binder particles accumulating in the friction zone.
Gegebenenfalls kann zwischen der Reinigungskammer und dem Bearbeitungsbehälter ein Pufferbehälter angeordnet sein, um eine Homogenisierung des Stoffgemischs vor der Bearbeitungszone zu erhalten und eine stets gleiche Schüttgutsäule im Bearbeitungsbehälter sicherzustellen.If necessary, a buffer container can be arranged between the cleaning chamber and the processing container in order to obtain a homogenization of the mixture of substances in front of the processing zone and to ensure that the bulk material column in the processing container is always the same.
Gemäß einer bevorzugten Ausführungsform ist vorgesehen, daß das Reibwerkzeug direkt über dem Boden des Bearbeitungsbehälters umläuft und der Ablauf in der Umlaufebene des Reibwerkzeugs angeordnet ist. Das Stoffgemisch wird also unmittelbar aus der Reibungszone weggeführt.According to a preferred embodiment, it is provided that the reaming tool rotates directly above the bottom of the processing container and the drain is arranged in the rotating plane of the reaming tool. The mixture of substances is therefore removed directly from the friction zone.
Das Reibwerkzeug kann zwei oder mehr Reibarme aufweisen, die bis in den Bereich des Umfangs des Bearbeitungsbehälters reichen.The reaming tool can have two or more rice arms which extend into the region of the circumference of the processing container.
Der Druck auf die Reibungszone kann ggf. dadurch erhöht werden, daß oberhalb des Reibwerkzeugs ein auf die Sandfüllung wirkendes Druckerzeugorgan, z.B. eine Schnecke, angeordnet ist.If necessary, the pressure on the friction zone can be increased in that a pressure generating element acting on the sand filling, for example a worm, acts above the grinding tool. is arranged.
In bevorzugter Ausführung ist vorgesehen, daß der Förderkreis von einer pneumatischen Fördereinrichtung gebildet ist, die am Ablauf des Bearbeitungsbehälters einen Injektor und eine von dort in die Reinigungskammer führende Förderleitung aufweist.In a preferred embodiment it is provided that the conveyor circuit is formed by a pneumatic conveyor device which has an injector at the outlet of the processing container and a conveyor line leading from there into the cleaning chamber.
Auf diese Weise wird auf die Reibungszone unmittelbar ein Unterdruck wirksam, der zu einer Reduzierung des Porenvolumens in der Reibungszone führt.In this way, a negative pressure acts directly on the friction zone, which leads to a reduction in the pore volume in the friction zone.
Die Reinigungskammer kann grundsätzlich beliebigen Aufbau aufweisen. In Verbindung mit einer pneumatischen Fördereinrichtung empfiehlt sich eine Ausbildung, bei der die Reinigungskammer als Zentrifugalabscheider ausgebildet ist und einen Staubabzug aufweist.The cleaning chamber can basically have any structure. In connection with a pneumatic conveying device, a design is recommended in which the cleaning chamber is designed as a centrifugal separator and has a dust extraction.
Schließlich kann der Bearbeitungsbehälter mehrere am Umfang verteilt angeordnete Abläufe aufweisen, um die Umlaufmenge zu erhöhen, ggf. auch steuern zu können. In einem solchen Fall ist an jeden Ablauf eine pneumatische Förderleitung angeschlossen.Finally, the processing container can have a plurality of processes distributed around the circumference in order to increase the circulation quantity, and possibly also to be able to control it. In such a case, a pneumatic delivery line is connected to each outlet.
Nachstehend ist die Erfindung anhand eines Ausführungsbeispieles beschrieben. In der Zeichnung zeigen:
- Figur 1:
- Eine schematische Ansicht einer Vorrichtung zum Aufbereiten von Altsand und
- Figur 2:
- eine schematische Ansicht einer Gesamtanlage.
- Figure 1:
- A schematic view of a device for processing used sand and
- Figure 2:
- a schematic view of an overall system.
In Fig. 1 ist ein Bearbeitungsbehälter 1 erkennbar, der an seiner Oberseite einen Zulauf 2 aufweist, der mittels einer Klappe 3 steuerbar ist. Unmittelbar oberhalb des Bodens 4 weist der Bearbeitungsbehälter 1 einen Ablauf 5 auf. Der Ablauf 5 mündet in eine pneumatische Förderleitung 6 mit Steigförderung. Die pneumatische Förderleitung 6 verbindet den Ablauf 5 mit einer Reinigungskammer 7 (siehe Fig. 2), die beim gezeigten Ausführungsbeispiel als Zentrifugalabscheider ausgebildet und auf ein Puffersilo 8 aufgesetzt ist. Das Puffersilo 8 wiederum steht über den Zulauf 2 mit dem Bearbeitungsbehälter 1 in Verbindung, so daß ein geschlossener Förderkreis vom Ablauf 5 des Bearbeitungsbehälters 1 über die Steigleitung 6, die Reinigungskammer 7, den Pufferbehälter 8 und den Zulauf 2 des Bearbeitungsbehälters hergestellt ist.In Fig. 1, a
Wie Fig. 2 zeigt, wird der in der Gießerei anfallende Altsand in einem Silo 9 gesammelt und von dort pneumatisch oder mechanisch, wie dies mit der Förderlinie 10 angedeutet ist, der Reinigungskammer 7 zugeführt und gelangt von dieser über das Puffersilo in den Bearbeitungsbehälter 1, um nach dessen Durchlauf über den Ablauf 5 und die Steigleitung 6 in die Reinigungskammer 7 rezirkuliert zu werden. An die Steigleitung 6 ist eine Zweigleitung 11 angeschlossen, die in ein Silo 12 führt, in der nach einer gewissen Anzahl von Arbeitszyklen im Bearbeitungsbehälter 1 der Regeneratsand gefördert wird. Vom Regenerat-Silo 12 wird der Sand in die Sandaufbereitung und/oder in die Kernherstellung der Gießerei abgezogen. Die Reinigungskammer 7 und die Silos 9, 10 sind ihrerseits an die Saugleitung 13 einer Entstaubungsanlage 14 angeschlossen.As shown in FIG. 2, the used sand accumulating in the foundry is collected in a silo 9 and, from there, pneumatically or mechanically, as indicated by the
Wie Fig. 1 zeigt, ist innerhalb des Bearbeitungsbehälters 1 unmittelbar oberhalb dessen Boden 4 ein umlaufendes Reibwerkzeug 15 angeordnet, das mehrere bis annähernd an den Umfang des Bearbeitungsbehälters 1 reichende Reibarme 16 aufweist. Das Reibwerkzeug 15 wird von einer unterhalb des Bodens gelagerten und diesen durchgreifenden Antriebswelle 17 in eine Umlaufbewegung versetzt. In Höhe des umlaufenden Reibwerkzeugs 15 ist der Bearbeitungsbehälter 1 innenseitig mit einer Verschleißschicht 18 ausgestattet.As shown in FIG. 1, a revolving
Die innerhalb des Bearbeitungsbehälters 1 befindliche Sandsäule lastet auf der von den Reibwerkzeugen 15 überstrichenen Reibungszone 19. Der Altsand läuft vornehmlich im mittleren Bereich in die Reibungszone 19 ein. Die in der Reibungszone befindlichen Sandpartikel werden intensiven Reibungskräften ausgesetzt, die die auf ihnen haftende Binderhülle abreibt. Die Sandpartikel und die Partikel der Binderhülle wandern aus der Reibungszone 19 nach außen in den Ablauf 5 und werden dort von der bei 20 eingeblasenen Förderluft über die Steigleitung 6 in die Reinigungskammer 7 transportiert. Durch die pneumatische Förderung entsteht am Ablauf 5 ein Unterdruck, der in der Reibungszone 19 zu einer Reduzierung des Porenvolumens führt. In der Reinigungskammer 7 werden die Sandpartikel durch Zentrifugal- und Gravitationskräfte abgeschieden, während die Binderpartikel über die Saugleitung 13 in die Entstaubungsanlage 14 gelangen. Der vorgereinigte Altsand gelangt aus der Reinigungszone 7 in den Pufferbehälter 8 und nach einer entsprechenden Verweilzeit wieder in den Bearbeitungsbehälter 1. Nach mehrfachem Durchlauf wird schließlich binderfreier Regeneratsand erhalten, der über die Förderleitung 11 in das Silo 12 abgezogen wird.The sand column located within the
Claims (18)
- Method for cleaning used foundry sand, in that the used sand is circulated in a treatment container and frictional forces are applied to the used sand particles which break open the binder shell and release same from the sand grain and the resulting material mixture of sand and binder particles is physically cleaned, whilst concentrating the sand fraction, characterized in that, after passing through the friction zone, part of the material mixture is drawn off from the treatment container into a separate cleaning container and cleaned and the precleaned used sand is returned to the treatment container.
- Method according to claim 1, characterized in that the material mixture or the precleaned used sand is recirculated several times between the treatment container and the cleaning container.
- Method according to claim 1 or 2, characterized in that the pore volume in the material mixture is reduced in the vicinity of the friction zone.
- Method according to one of the claims 1 to 3, characterized in that the material mixture is compacted by mechanical pressure in the vicinity of the friction zone.
- Method according to one of the claims 1 to 4, characterized in that in connection with the drawing off of the material mixture from the treatment container, air is sucked out of the friction zone.
- Method according to one of the claims 1 to 5, characterized in that the used sand batch in the treatment container is moved under gravity from top to bottom into the friction zone and in the vicinity thereof the material mixture is drawn off substantially horizontally outwards.
- Method according to one of the claims 1 to 6, characterized in that, in the vicinity of the friction zone, the material mixture is mechanically outwardly displaced and pneumatically removed at the treatment container periphery.
- Apparatus for regenerating used foundry sand having a treatment container (1), which has a controllable inlet (2), on its circumference, just above the bottom (4), an outlet (5) and at least one friction tool (15) circulating above the bottom (4), characterized in that, outside the treatment container (1), is provided a cleaning container (7) for separating sand and binder particles and which is located in a feed cycle linking the outlet (5) of the treatment container (1) to its inlet (2).
- Apparatus according to claim 8, characterized in that a buffer container (8) is positioned between the cleaning container (7) and the treatment container (1).
- Apparatus according to claim 8 or 9, characterized in that the friction tool (15) circulates directly above the bottom (4) of the treatment container (1) and the outlet (5) is located in the circumferential plane of the friction tool (15).
- Apparatus according to one of the claims 8 to 10, characterized in that the friction tool (15) has two or more friction arms (16) extending into the vicinity of the circumference of the treatment container (1).
- Apparatus according to one of the claims 8 to 11, characterized in that above the friction tool (15) is positioned a pressure generating member, e.g. a worm acting on the sand filling.
- Apparatus according to one of the claims 8 to 12, characterized in that the feed cycle is formed by a pneumatic feed mechanism, which has in the outlet (5) of the treatment container (1) an injector and a feed line (6) leading therefrom into the cleaning container (7).
- Apparatus according to one of the claims 8 to 13, characterized in that the cleaning container (7) is constructed as a centrifugal separator and has a dust exhaust fan.
- Apparatus according to one of the claims 8 to 14, characterized in that the treatment container (1) has several circumferentially distributed outlets (5).
- Apparatus according to one of the claims 9 to 15, characterized in that the buffer container (8) receives 5 to 50, preferably 10 to 20 batch volumes of the treatment container (1).
- Apparatus according to one of the claims 8 to 16, characterized in that several treatment containers and cleaning containers (7) are connected in series.
- Apparatus according to one of the claims 9 to 17, characterized in that several treatment containers (1) are connected by means of one or more cleaning containers (7) to a buffer container (8).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4237838A DE4237838A1 (en) | 1992-11-10 | 1992-11-10 | Method and device for regenerating foundry sand |
| DE4237838 | 1992-11-10 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0597335A1 EP0597335A1 (en) | 1994-05-18 |
| EP0597335B1 true EP0597335B1 (en) | 1997-07-23 |
Family
ID=6472470
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP93117552A Expired - Lifetime EP0597335B1 (en) | 1992-11-10 | 1993-10-29 | Process and apparatus for renerating used foundry sand |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0597335B1 (en) |
| DE (2) | DE4237838A1 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8632850B2 (en) | 2005-09-26 | 2014-01-21 | Schultz-Creehan Holdings, Inc. | Friction fabrication tools |
| US8636194B2 (en) | 2005-09-26 | 2014-01-28 | Schultz-Creehan Holdings, Inc. | Friction stir fabrication |
| US8875976B2 (en) | 2005-09-26 | 2014-11-04 | Aeroprobe Corporation | System for continuous feeding of filler material for friction stir welding, processing and fabrication |
| US9266191B2 (en) | 2013-12-18 | 2016-02-23 | Aeroprobe Corporation | Fabrication of monolithic stiffening ribs on metallic sheets |
| US9511445B2 (en) | 2014-12-17 | 2016-12-06 | Aeroprobe Corporation | Solid state joining using additive friction stir processing |
| US9511446B2 (en) | 2014-12-17 | 2016-12-06 | Aeroprobe Corporation | In-situ interlocking of metals using additive friction stir processing |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4318136A1 (en) * | 1993-06-01 | 1994-12-08 | Badische Maschf Gmbh | Process for regenerating foundry old sands |
| DE10025815C2 (en) * | 2000-05-24 | 2002-08-01 | Cyrus Gmbh Schwingtechnik | Sand recovery device |
| WO2013002869A2 (en) * | 2011-04-07 | 2013-01-03 | Schultz-Creehan Holdings, Inc. | System for continuous feeding of filler material for friction stir fabrication and self-reacting friction stir welding tool |
| DE102015006152B4 (en) | 2015-05-12 | 2018-06-07 | Mueg Mitteldeutsche Umwelt Und Entsorgung Gmbh | Process for the preparation and reuse of foundry sands |
| CN111655403B (en) | 2017-10-31 | 2022-10-14 | 梅尔德制造公司 | Solid additive manufacturing system and composition and structure of material |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1195226A (en) * | 1966-08-04 | 1970-06-17 | British Cast Iron Res Ass | Reclamation of Moulding Sand |
| DE3309379A1 (en) * | 1983-03-16 | 1984-09-20 | Hubert Eirich | METHOD FOR REGENERATING FOUNDRY SAND AND DEVICE FOR IMPLEMENTING THE METHOD |
| DE3873522D1 (en) * | 1988-05-26 | 1992-09-10 | Pohl Giessereitechnik | METHOD AND DEVICE FOR REGENERATING FOUNDRY SAND. |
| CH682986A5 (en) * | 1990-03-08 | 1993-12-31 | Fischer Ag Georg | A process for the batch regeneration treatment of predominantly clay bonded foundry used sand. |
| DE4111726C2 (en) * | 1991-04-10 | 1994-02-24 | Kgt Giessereitechnik Gmbh | Process for mechanical cleaning of foundry sand |
-
1992
- 1992-11-10 DE DE4237838A patent/DE4237838A1/en not_active Ceased
-
1993
- 1993-10-29 DE DE59306964T patent/DE59306964D1/en not_active Expired - Fee Related
- 1993-10-29 EP EP93117552A patent/EP0597335B1/en not_active Expired - Lifetime
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8632850B2 (en) | 2005-09-26 | 2014-01-21 | Schultz-Creehan Holdings, Inc. | Friction fabrication tools |
| US8636194B2 (en) | 2005-09-26 | 2014-01-28 | Schultz-Creehan Holdings, Inc. | Friction stir fabrication |
| US8875976B2 (en) | 2005-09-26 | 2014-11-04 | Aeroprobe Corporation | System for continuous feeding of filler material for friction stir welding, processing and fabrication |
| US8893954B2 (en) | 2005-09-26 | 2014-11-25 | Aeroprobe Corporation | Friction stir fabrication |
| US9205578B2 (en) | 2005-09-26 | 2015-12-08 | Aeroprobe Corporation | Fabrication tools for exerting normal forces on feedstock |
| US9266191B2 (en) | 2013-12-18 | 2016-02-23 | Aeroprobe Corporation | Fabrication of monolithic stiffening ribs on metallic sheets |
| US9511445B2 (en) | 2014-12-17 | 2016-12-06 | Aeroprobe Corporation | Solid state joining using additive friction stir processing |
| US9511446B2 (en) | 2014-12-17 | 2016-12-06 | Aeroprobe Corporation | In-situ interlocking of metals using additive friction stir processing |
Also Published As
| Publication number | Publication date |
|---|---|
| DE59306964D1 (en) | 1997-08-28 |
| EP0597335A1 (en) | 1994-05-18 |
| DE4237838A1 (en) | 1994-05-11 |
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